The precautionary measure involves spraying the inside of aircraft to reduce the risk of mosquito bites on board, the UK Department of Health said.

'Disinsection' is not a new process - it already occurs on the majority of flights from the region as a precaution against malaria.

Zika is spreading "explosively" in Latin America, according to the World Health Organisation (WHO), which says the outbreak is a global health emergency.

Experts say it may only be a matter of time before the virus reaches popular holiday destinations like Spain, Portugal, Greece, France, Italy and the southern US, where the Aedes mosquito - which transmits the disease - is active.

"There is little doubt that Zika viral infections will continue to be reported from many other countries where the Aedes mosquito is found," says Dr. Graham Fry, Medical Director of the Tropical Medical Bureau in Ireland.

"This includes many southern European countries - especially as we head into the summer months when the correct breeding conditions (heat and humidity) occur."

Transmission of the virus has not yet been reported in Europe, although several cases have been diagnosed in returned travellers, including two in Ireland.

Irish tour operators including Falcon, American Holidays and Travelmood are permitting pregnant concerned about travel to affected countries to change their bookings, as long as they provide a doctor's note.

Sunway and Tropical Sky have said they are reviewing cancellation and amendment requests on a case-by-case basis, Independent.ie Travel has learned.

The Department of Foreign Affairs has advised women who are pregnant, or considering pregnancy, to consult their family doctor and to consider postponing travel to affected areas.

Though Irish travellers may contract the virus overseas, there is little danger of the Aedes mosquito surviving in Ireland, Dr Fry said.